By TRACI PEDERSEN Associate News Editor, PsychCentral.comReviewed by John M. Grohol, Psy.D. on July 7, 2013.

With the right incentive — such as winning a prize — children with autism do fairly well at inferring the thoughts and beliefs of others, according to a study published in the journal Developmental Science.

Previous studies have shown that children with autism usually struggle with inferring the thoughts of others in a common test designed to measure this ability, known as “theory of mind.”

The new study suggests that they are able to grasp theory of mind, but don’t have a strong enough motivation to give the correct answer while taking the classic test.

The specific of the test vary, but children are usually told a story in which two characters (often called Sally and Ann) place an object in a basket. After Sally leaves the room, Ann moves the item into a box.

The child passes the test if he or she knows that Sally will look for the item in the basket and not the box.

Normally developing children struggle with this test at three years of age, then most pass it by the time they are five years old. But the majority of children with autism continue to fail the test well into their teenage years.

Adults with autism are usually able to pass the Sally-Ann test but struggle with more subtle examples of theory of mind.

In the new study, the Sally-Ann test was turned into a game.

For typically developing kids, the motivation to answer a question correctly may be tied to a desire for social interactions. In contrast, children with autism may use theory of mind when they want something concrete, for example when competing for things with a sibling, the researchers said.

In the new test, the children think they’re competing with two people — named Dot and Midge — for a toy car or ball, and whoever finds the toy first gets to keep it.

Similar to the Sally-Ann test, the researchers put the toy in one container and then move it after one participant (Midge) leaves the room. The children have to wait for either Dot or Midge to try to win the toy before they get a turn. But they get to decide whether Dot or Midge goes first. If they understand that Midge doesn’t know where the toy was moved to, they will more likely pick her.

The researchers gave both the Dot-Midge and the Sally-Ann test (using dolls to represent the two characters in the Sally-Ann test) to 23 high-functioning children with autism between the ages of 7 and 13, and 73 typically developing children.

All the kids were then split into three groups with an average age of 3 years, 4 years and 2 months, and 4 years and 8 months. Each participant took the tests two times.

As expected, only 3 of the 23 children with autism answered the Sally-Ann test correctly both times. But 17 of them got a perfect score on the Dot-Midge test, answering correctly both times.

Similarly, not all typical 4-year-olds answered correctly on the Sally-Ann test, but 13 of 24 younger 4-year-olds and 20 of 26 older 4-year-olds passed the Dot-Midge test. The typical 3-year-olds did poorly on both tests. This suggests that the Dot-Midge test reveals theory of mind at a younger age than does the Sally-Ann test, said the researchers.